United States. Department of the Treasury. "Report of the Secretary of the Treasury on the State of the Finances for the Year 1868,"
Annual Report of the Secretary of the Treasury on the State of the Finances
(1868).
https://fraser.stlouisfed.org/content/?item_id=5512&filepath=/files/docs/publications/treasar/AR_TREASURY_1868.pdf, accessed on May 24, 2018.